Verfahren zur Herstellung von unsymmetrischen Thiol- bzw. Thionothiolphosphorsaeureestern

摘要

The invention comprises compounds of the general formula wherein R1 stands for a linear alkyl radical (preferably of from 1-4 carbon atoms), R2 represents a branched alkyl radical or cycloalkyl radical, preferably isopropyl or sec.- and tert.-butyl radical, or pinacolyl or cyclohexyl radical, and X is oxygen or sulphur. They can be prepared by reacting an appropriate N-halo-methyl-benzazimide with an appropriate asymmetric O,O-dialkyl or O-alkyl-O-cycloalkyl-thiol or thionothiolo-phosphoric acid in the presence of an acid-binding agent or with a salt (e.g. alkali metal or ammonium salt) of the said thiolo- or thionothiolo-phosphoric acid. The reaction is preferably carried out in an inert organic solvent such as an aliphatic ketone, an aliphatic nitrile, or an aromatic hydrocarbon. The reaction is suitably carried out at a moderately elevated temperature, e.g. 30 DEG to 100 DEG C. The products have pesticidal properties (see Division A5). The thiophosphoric acids used as starting materials can be prepared by mixing appropriate quantities of a linear aliphatic alcohol and a branched aliphatic alcohol or a cycloaliphatic alcohol and stirring at an elevated temperature with phosphorus pentasulphide.ALSO:A pesticidal composition comprises an inert solid or liquid diluent or carrier and a compound of the general formula: wherein R1 stands for a linear alkyl radical (preferably of from 1-4 carbon atoms), R2 represents a branched alkyl radical or cycloalkyl radical, preferably iso-propyl or sec. and tert-butyl radical or pinacolyl or cyclohexyl radical and X is oxygen or sulphur. The composition may be an emulsifiable concentrate, a spray powder, a paste, a soluble powder, a dusting agent or a granulate. Dispersible liquid carrier vehicles include solvents such as halogenated aromatic hydrocarbons, paraffins, ether, alcohols, amines, and dimethyl formamide. Finely divided solid carrier vehicles include, natural or synthetic rock meals or powders. Liquid emulsifiers such as non-ionic and anionic emulsifiers as well as dispersing agents, for example methyl cellulose and lignin may be present. Known pesticides may also be present. The active ingredient may be used to combat pests by applying it to a pest habitat either alone or in admixture with a carrier.